1. Technical Field
The invention concerns a method of controlling call routing through a communications network, and a communication terminal.
2. Discussion of Related Art
The invention starts with a communication system as described in EP 0738093. In this communication system a subscriber can be reached with a standardized call number, although he may have different types of communication terminals such as for example ISDN, GSM or DECT terminals, whereby he can be alternately reached.
A connection request directed to the subscriber is routed to a central network node of the communication system. This node translates the personal call number of the subscriber into the physical call number of the particular terminal for which the subscriber is registered. The connection is subsequently routed to the particular terminal for which the subscriber is registered.
In this case the registration takes place manually by the subscriber sending an explicit control message to the central node, or automatically through a DECT (Digital European Cordless Telephone) when the subscriber with his DECT terminal has moved into its covered range. The radio network base station of the DECT's access system detects the entrance of the DECT into its covered range and performs the registration in the central node.
A computer-controlled radio subscriber terminal which is suitable for operation in mobile radio networks with different system technologies, is known from EP 0297616 A1.
This subscriber radio terminal has two communication units. One of the communication units provides the means required to communicate via a first mobile radio network, and the other communication unit provides the means for communicating via a second, different type of mobile radio network. The subscriber radio terminal furthermore has an evaluation device which determines by means of the field strength of both mobile radio networks which one of the two communication units is activated and which one is blocked.